Refrigerator door



May 17 1955 o. v. sAuNDERs 2,708,294

REFRIGERATOR DooR Filed Sept. 23, 1953 2 Sheets-Sheet 1 Fig.

INVENTOR Orson V. Saunders His Airarney.

May 17, 1955 C. 'V SAUNDERS REFRIGERATOR DOOR Filed Sept 23, 1953 2Sheets-Sheet 2 Fig .S mw Td Nn Eu Va m8 V. n ,f O

HisVV Attorney.

Unite States Patent O REFRIGERATR DR Orson V. Saunders, Dayton, Ohio,assigner to General Motors Corporation, Detroit, Mich., a corporation ofDelaware Application September 23, 1953, Serial No. 381,771

2 Claims. (Cl. 203S) This invention relates to closure members forfreezing compartments of refrigerator cabinets.

In that type of refrigerator wherein frozen foods as well as unfrozenfoods are stored in adjacent compartments there is an appreciabletemperature differential between the frozen food storage compartment andthe unfrozen food storage compartment. It is the practice to provide afreezing or frozen food storage compartment Within the conventional foodstorage chamber of a household refrigerator cabinet and to utilize aninsulated door structure for closing the access opening of the frozenfood compartment which is separate from and operable independently of anouter door employed to close the ac cess opening of the main foodstorage chamber containing unfrozen foods. Due to the fact that theseinner doors are assembled at room temperature and then mounted in arefrigerator cabinet wherein the temperature to which the inner andouter panels of the door are exposed is considerably differentdifficulty has been experienced. This difficulty arises because of thefact that the panels of such doors, whether they are formed of likematerial or dissimilar materials, are usually rigidly connected togetherat a plurality of points around their sides and when the inner and outerfaces of the door are ex posed to different temperatures one panel willexpand and/or contract more or less than the other panel and cause wmageor twisting of the door resulting in misalignment thereof with the frontof a compartment to be closed thereby. This is particularly true ofdoors having one metal panel and a molded plastic panel.

An object of my invention is to provide an improved door construction oflow manufacturing cost which may be assembled at room temperature andthereafter subjected to a higher or a lower temperature without becomingwarped or damaged.

Another obiect of my invention is to provide an elon- Y gated orrectangular insulated door structure with a metal outer panel and aninner molded plastic panel each adapted to be exposed to differentenvironment having appreciable temperature differentials therebetweenwhich structure includes means for interlockingly connecting the panelsto one another in a fashion to prevent Warpage of the door.

A further object of my invention is to interlockingly connect a moldedthermoplastic door panel to a sheet metal door panel in a manner topermit expansion and/ or contraction of the molded plastic panel in adirection paralleling the extension of the metal panel so as to preventbowing and twisting of the molded plastic panel and Warpage of or damageto the door.

ln carrying out the foregoing objects it is a still further and morespecific object of my invention to provide ange means along certainsides of an outer metal panel of an elongated or rectangular insulateddoor strucnire for slidably receiving a groove along side edges of amolded plastic inner door panel to interlockingly connect the panels toone another and to arrange the interlocking connection in such fashionas to permit free expansion Vice and/ or contraction of the inner panelrelative to the outer panel while holding the inner pane against bowingor twisting during its expansion and/ or contraction whereby warpage ofthe door is minimized to prevent misalignment thereof with the front ofthe compartment to be closed thereby.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

ln the drawings:

Figure l is a perspective view showing a refrigerator having a doorconstructed in accordance with my invention mounted therein;

Figure 2 is an enlarged fragmentary view taken on the lino 2 2 of Figurel partly in section and partly in elevation showing my improved doorclosing a freezing compartment within the refrigerator cabinet;

Figure 3 is a View looking toward the inner face of my improved door andis taken on the line 3 3 of Figure 2;

Figure 4 is an enlarged fragmentary vertical sectional view taken on theline 4--4 of Figure 3 showing the interlock connection of panels of thedoor at a point intermediate its sides;

Figure 5 is a view similar to Figure 4 taken on the the line 5-5 ofFigure 3 and shows the interlock connection of panels of the door beyondthe central part thereof;

Figure 6 is an enlarged View taken on the line 6 5 of igure 4 showing athickened central top edge portion of the door inner panel fitting in acut out part of thc outer metal door panel; and

Figure 7 is a sectional View of the interlock between the door panelsalong the short sides of the door.

Referring now to the drawings, for illustrating my present invention, Ishow in Figure 1 thereof a refrigerator cabinet generally represented bythe reference character 10. Cabinet 1t? includes the usual outer wallsand a metal liner 11 spaced therefrom and providing walls of a main foodstorage chamber 12 therein. Any suitable or desirable insulatingmaterial 13 (see Figure 2) is placed in the space between liner 11 andthe cabinet outer walls as is conventional in the art. An insulatedbox-like structure is mounted, by any suitable or desirable means, inthe upper portion of the main or unfrozen food storage chamber 12 toprovide a freezing or frozen food storage compartment 14 within chamber12. The box-like structure forming frozen food compartment 14 (seeFigure 2) includes an outer metal shell 16, an inner metal liner 17,with insulating material 18 disposed therebetween, and a sealing member19 at the access opening of compartment 14. Sealing member 19 comprisesa rigid insulating backing piece secured between and spacing the frontedges of walls 16 and 17 of compartment 14 apart. This sealing member isprovided with an outer door engaging face of soft resilient foam rubberor the like material. An outer door 21 is provided as shown for normallyclosing the open front of the refrigerator cabinet, affording access tochamber 12. A separate rectangularly shaped or horizontally elongatedinner door structure, generally represented by the reference character23, is adapted to engage the outer face of the sealing member 19 andserves as a closure member for closing the front access opening ofcompartment 14. Any suitable or desirable handle means (not shown) maybe provided on door 23 t0 facilitate operating the same. Different lowtemperatures are maintained in chamber 12 and compartment 14 andtherefore they form zones having an appreciable temperaturedifferential. Compartment or zone 14 and chamber or zone 12 are adaptedto be refrigerated respectively by means ofV a conventionalrefrigerating systern (not shown) which may include a primary evaporatoror refrigerant evaporating conduit coils 26 wrapped around and securedin intimate thermal contact with the inner liner i7 of the frozen foodstorage compartment 14 (see Figure 2) and a plate type or sheet metalevaporator 27 suitably mounted in the upper rear portion of the foodchamber l2 (see Figure l). The detailed construction and arrangement ofthe refrigerating system may be varied at will and for this reason aspecific description of the elements and connections therebetween ofsuch a system is unnecessary because the refrigerating system forms nopart of the subject matter claimed herein.

The rectangular inner door structure 23 comprises or includes a sheetmetal outer front panel 3l and a molded thermoplastic inner or rearpanel 32. These door panels are connected together in a manner to bepresently described and packaged insulating material 33, preferably ofVwrapped or spun glass or rock wool, is disposedV in the spacetherebetween. Door 23 is pivotally supported at the proper locationwithin chamber l2, to close the open front of compartment 14, from apair of side mounting brackets 34'journalled on stationary pins 35secured to and carried by liner 1l. The molded plastic inner door panel32 is preferably molded from powdered styrene which is heated and forcedinto a suitable panel forming mold. Other material such aspolyvinyl-acetate or polyvinyl-chloride may, if desired, be employed toform panel 32 of door 23. Door 23 is usually assembled at roomtemperatures and due to the high coeiicient of expansion and contractionof plastic materials and the difference in temperature to which theinner and outer faces of door 23 may be exposed special provisions mustbe incorporated in the door structure 23 to prevent Warpage thereof. Forexample, after door 23 has been assembled at room temperature and thenstored or shipped at higher or lower temperatures an appreciable amountof expansion of the molded plastic panel 32 relative to the sheet metalpanel 3i and contraction thereof respectively relative to paneL 31 willtake place. Also when door 23 is mounted in the refrigerator cabinet 10,herein disclosed, and the refrigerator installed and placed in operationthe inner molded plastic panel 32 of door 23 is subjected to a lowtemperature of around 5 to 10 F.

of the interior of freezing or frozen food compartment 'f 14 while theouter sheet metal panel 3l of door 23 is eX- posed to the highertemperature of approximately 38 to 45 F. of the main unfrozen foodstorage chamber or compartment i2. When both doors 21 and 23 are openedthe inner molded plastic panel 32 of door 23 is subjected to a muchhigher temperature approximating the ternperature of the room in whichthe refrigerator cabinet it? is installed. The exposure of such aninsulated rerigerator cabinet door to these wide Vtemperaturedifferentials renders it diicult to prevent warpage of door 23 andmaintenance of a goed seal of this door with the door engaging sealingmember i9 at the front or access opening of the insulated box-likestructure forming the food freezing or frozen food storage compartment14 within the refrigerator 10.

vin accordance with my invention l desire to construct an elongated orrectangular door forming a closure member between zones having anappreciable temperature ditferential which door will not, under theconditions described, become warped out of its original aligned or ilatassembled position or be damaged. in order to accomplish thisdesideraturn l have found that an insulated paneled door structure foruse in a refrigerator cabinet at the location specified its moldedplastic panel must be interloclced with the metal panel thereof in afashion to permit expansion and/or contraction of the molded plasticpanel in a direction paralleling the eX- tension of the metal panel.When provisions are made to permit such expansion and/or contraction ofthe molded plastic panel this panel will not have a tendency to bow ortwist and therefore the door does not warp or become damaged. Bysiidably interlocking a molded plastic door panel to at least twoopposed sides of the sheet metal door panel and by rigidly clamping theplastic panel to the sheet metal panel only at points centrally of thelength of the door side portions the molded plastic door panel mayexpand or contract, beyond the rigid clamping points, relative to themetal door panel while being held in parallel relation to the metalpanel. Thus in the present arrangement sheet metal panel 31 of door 23is flanged toward the molded plastic panel 32 as at 41 about four sidesof the door and is bentas at 42 to provide a recess in the front facethereof (see Figures 4, 5, and 7). It is believed to be obvious that theanges or continuous ange 4l and the bent parts 42 of door panel 31greatly increase its structural strength and provides a rather rigiddoor pan or panel to which another panel may be attached. A part offlangey 41 adjacent its edge is bent substantially at a right anglethereto as at 43 (see Figures 4, 5, 6, and 7) to provide a tongue aboutthe horizontal top side and the two vertical sides of door 23 (seeFigure 3). The flange All at the bottom of doorr23 also has a partadjacent its edge bent upwardly to provide another tongue 44. It will benoted by reference to Figures 4 and 5 of the drawings that anothertongue 44E is offset inwardly relative to tongue 43 to provide the door23 with one long side, the bottom side thereof, which is thinner thanthe other three sides of the door and is for a purpose to be hereinafterdescribed.

rl'he molded formed on one of its surfaces, preferably the inner surfacethereof, any desirable integral embossed strength-V ening beads or ribsof suitable extension and shape such as the cross d'7 indicated inFigure 3 of the drawings. The elongated or rectangular inner moldedplastic door panel 32 is provided with a thickened edge portion 48 (seeFigures 4, 5, and 7) extending along its long top and opposed shortsides. Panel 32 is also provided with a lower inwardly offset angeVportion 49 which abuts the tongue on panel 31 and is adapted to besecured thereto. The thickened edge portion 4S about the three sides ofpanel 32 has a groove 5l providedtherein and the opening of this groovefaces or is directed toward the edge of these sides of panel 32. Tongue,43 on metal panel 31 fits in the groove Si to interlockingly connectmolded plastic panel 32 to panel 3l about three sides of door 23. lt isto be noted that the lips or side walls of grooves 51 firmly abut thesides of tongues 43 and that a clearance is provided between the end oredge of tongues 43 and Athe inner wall of groove Si. vfhe existence ofthis clearance is important in that it provides for a predeterminedamount of expansion and/or contraction of molded plastic panel 32 in adirection paralleling the tongues 43 and consequently the extension ofouter metal panel 3l as will be more specifically described hereinafter.The groove 51 has a short raised portion 53 therein located centrallybetween the two opposed short sides of doorV 23 as shown in Figures 3,4, and 6 of the drawings. Tongues 43 along the upper long side of metalpanel 3i are cut out as at 54 (see Figure 7) to receive and straddle theraised portion 53 of panel 32. f

A screw 56, located substantially midway between the short sides of door23 (see Figure 3), passes through an opening 57 in flange $9 of themolded plastic inner panel 32 (see Fignre 4) and is threaded into atapped hole provided in the lower tongue ed of'rnetal outer panel 31.This screw :E6-forms a separate means for securing one edge portion ofthe panels 3l and 32 together to maintain the interlocking connectionbetween the panels. The opening 57 is of a diameter substantially equalto the diameter of the shank part of screw 56 so that this screw 56serves to center the plastic panel 32 with respect to Vmetal panel 3l toprovide the clearance heretofore mentioned between the end of each ofthe tongues 43 and the inner wall of grooves 51. This screw S6 isplastic panel 32 of door 23 may have avoaeoa rrnly tightened to rigidlyclamp the plastic panel 32 to metal panel 3l at a central point on door23 intermediate its two opposed short sides (see Figures 3 and 4). Ascrew 5S, located adjacent each end or short side of door 23, passesthrough an opening 59 in dange 49 cf panel 32 (see Figures 3 and 5) andis also threaded into a tapped hole provided in the tongue 44 of theouter panel 3l. Openings 59 are larger in diameter than the shanl;portion of screws 53 to permit that portion of the molded plastic panel32 adjacent these screws to slide slip relative thereto under the headsthereof upon expansion and/or contraction of panel 32 in a directionparalleling panel 3l. The close fit of raised portion 53 of groove 51 atits vertical side with cut out portion 54 of tongue 43, at the centraltop part of door 23, together with wall of opening 57 in panel 32closely embracing the shank part of screw 56 rigidly clamps the panelsto one another. The tongue and groove interlocking arrangement of thepanels to one another as disclosed permits expansion and/or contractionof molded plastic panel 32 from the points of rigid connection betweenthe panels in a direction paralleling metal panel 3l while holding themolded plastic panel against bowing or twisting.

In assembling door structure 23 the bagged insulating material 33 isplaced within the outer metal door pan or panel 3l and the moldedplastic inner panel 32 is slid in a direction from the lower or fourthside of the door upwardly relative to panel 3l. The tongue 44 beingoffset inwardly of tongues 43 provides space to align the grooves 51with the tongues 43 at the short sides of the door and to permit theirentry into the grooves Sl. The panel 32 is slid upwardly into engagementwith panel 3l. until the tongues 43 about three sides of door 23 fitinto the grooves 5l therealong to interlockingly connect the panelstogether. Raised portion 53 along the inner wall of groove 5l is guidedinto the cut out part 54 of tongue 43 at the top of door 23 and thisaligns opening 57 with the central tapped hole in the other or lowertongue 44. Screw S6 is then placed in opening 57 and tightly threadedinto the central tapped hole in tongue 44 of outer metal panel 31 so asto maintain the interlock between the panels. Thereafter screws 58 arepassed through openings 59 and threaded into the tapped holes in thetongue 44 to complete the securement of panels 31 and 32 to one another.

The feature of rigidly holding the molded plastic panel 32 at a pointmidway between the short sides of the door to the metal panel 3l, theinterlocking of the three side edges of panel 32 to panel 3l and theprovision of clearance between the inner wall of grooves 51 and the endsor edges of the tongues 43 on panel 3l all con tribute to permitting themolded plastic panel to expand and/ or contract relative to metal panel31 without twist4 ing or bowing. By interlocking panel 32 to panel 31 inthe manner disclosed to allow it to expand and contract in a directionparalleling the extension of metal panel 31 the molded plastic paneldoes not tend to warp door 23 and therefore this door retains itsoriginal flat shape to engage the freezing compartment access openingsealing member 19 uniformly therearound under different temperatureconditions to which panel 32 may be subjected. The present structure isa simple arrangement which can be produced at low manufacturing costsbecause a minimum of parts are employed to accomplish the objects. Therigid metal panel counteracts any tendency of the molded plastic panelto twist or bow and thus warpage of the door is prevented while theouter molded plastic panel thereof may freely expand or contract.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, as may come within the scope of the claims whichfollow.

What is claimed is as follows:

l. An elongated rectangular door structure of the type adapted to form aclosure between Zones having an appreciable temperature differential,said structure comprising inner and outer panels forming a spacetherebetween, insulating material disposed in and substantially llingthe space between said panels, one of said panels being formed of sheetmetal and the other of said panels being of molded plastic materialhaving characteristics of greater expansion and/or contraction uponchanges in temperature thereof relative to said metal panel, said sheetmetal panel being ilanged about its periphery and provided with a tonguedirected inwardly of at least two short sides thereof, said moldedplastic panel having a groove along each of its short sides with theopening thereof facing said tongue on the short sides of said metalpanel, said molded plastic panel being slid luto engagement with saidmetal panel from one long side thereof with said tongues iitted in saidgrooves, means rigidly locking the edge portions of said panels togetheragainst slippage relative to one another at a single point on each ofthe long sides thereof substantially midway between their short sides,the bottom wall of said grooves normally being spaced from the end ofsaid tongues to permit said molded plastic panel to expand and/orcontract away from and toward said locking points in a directionparalleling the extension of said metal panel, and the width of saidgrooves being substantailly equal to the thickness of said tongueswhereby the side walls of said grooves each engage an opposed side ofsaid tongues during expansion and/ or contraction of Said molded plasticpanel to prevent twisting thereof relative to said metal panel.

2. An elongated rectangular door structure of the type adapted to form aclosure etween zones having an appreciable temperature differential,said structure com- Jnee insulating material disposed in andsubstantially filling the space beta/'een said panels, one of saidpanels being formed of sheet metal and the other of said panels being ofmolded plastic material having characteristics of greater expansionand/or contraction upon changes in temperature thereof relative to saidmetal panel, said sheet metal panel being iianged about its peripheryand provided with a tongue directed inwardly of one of its long sidesand both of its short sides, said molded plastic panel having acontinuous groove along one of its long sides and along both of itsshort sides With the opening thereof facing said tongue on the threesides or" said metal panel, said molded plastic panel being slid intoengagement with said metal panel from the fourth side thereof with saidtongues fitted in said grooves, means rigidly locking the edge portionsof said panels together against slippage relative to one another at asingle point on each of the long sides thereof substantially midwaybetween their short sides, the bottoni wall of said grooves normallybeing spaced from the end of said tongues to permit said molded plasticpanel to expand and/or contract away from and toward said locking pointsin a direction paralleling said metal panel, and the width of saidgrooves being substantially equal to the thickness of said tongueswhereby the side walls of said grooves each engage an opposed side ofsaid tongues continuously along their length during expansion and/orcontraction of said molded plastic panel to prevent twisting thereofrelative to said metal panel.

References Cited in the ille of this patent UNITED STATES PATENTS1,329,340 Hillman lan. 27, 1920 2,336,644 Soulier! Dec. 14, 19432,558,599 Wiles lune 26, l951 2,629,141 Palmer Feb. 24, 1953 2,661,118Bennighof Dec. 1, 1953 2,675,141 Schmelig Apr. 13, 1954

